WASHINGTON — Beginning pilots could substitute “structured and disciplined” classroom training for flying experience in qualifying to work for airlines under legislation approved Thursday by a Senate panel.

The provision would change minimum pilot training requirements the Federal Aviation Administration adopted after the last fatal crash of a U.S. passenger airline in 2009.

Regional airlines, which contend there is a shortage of qualified pilots, have long sought to soften an FAA requirement after the crash that all pilots have at least 1,500 hours of flying experience. But critics said weakening the standard would mean writing new regulations in the "blood" of crash victims.

Sen. John Thune, R-S.D., said the goal of his provision added to broader FAA legislation by a narrowly divided Commerce, Science and Transportation Committee is to provide better quality training rather than a quantity of flying hours.

“The amendment would allow prospective pilots to receive credit toward flight-hour requirements if taking structured and disciplined training courses if completion of those training courses will enhance safety more than an unstructured accumulation of flight hours,” Thune said.

But Sen. Tammy Duckworth, D-Ill., a former Army combat pilot, said watching videos in a hotel ballroom can’t replace flying experience. She compared the 1,100 deaths from airline accidents from 1990 through 2009 to the lack of fatalities in passenger-airline accidents since the 1,500-rule was adopted. Co-pilots used to qualify with 250 hours of flight time, rather than the 1,500 hours required of captains.

“If we vote for this, we will be writing future regulations in blood,” Duckworth said.

Duckworth tried to block the provision but lost on a 14-13 vote. The committee then adopted the provision by voice vote.

Lawmakers agreed to try and negotiate a compromise before the legislation reaches the Senate floor because Minority Leader Charles Schumer, D-N.Y., has threatened to block the entire FAA bill if the provision is included.

The training requirement sparks an emotional debate because relatives of the 50 victims of the last fatal crash — Colgan Air Flight 3407 in February 2009 near Buffalo — attend congressional hearings and voting sessions to fight for safety standards.

Ten-year-old Summer West of Clarence, N.Y., whose father, Ernie, died in the Colgan crash, told lawmakers before a House vote Tuesday that they and the pilots commanding planes were supposed to protect passengers rather than weaken safety measures.

“My daddy was funny, kind, smart and always protected me. But I couldn’t protect him because I was only 2 years old when he was killed in a plane crash,” Summer said. “But I can protect other daddies now, and make sure my daddy’s death wasn’t all for nothing.”

“The system is not broken,” Maurer said. “Short-changing safety is not the way to go.”

Investigators found Colgan pilots made mistakes that stalled their turboprop plane in a snowstorm. Regulators developed new rules for pilot qualifications, training and fatigue.

In 2010 legislation, Congress required that airline co-pilots, also known as first officers, get the same 1,500 hours of flight time as captains.

The Transportation Department regulations finalized in July 2013 made exceptions for military pilots who have flown at least 750 hours, graduates of four-year colleges who have flown at least 1,000 hours and graduates of two-year colleges who have flown 1,250 hours.

Regional airlines, which provide about half the country’s flights, have long argued that training requirements make it difficult to find qualified pilots. Flights to smaller cities are jeopardized if airlines can’t find pilots to fly the planes.

Thune said two-thirds of the country’s airports are served exclusively by regional airlines, and the training requirement contributes to their difficulties hiring pilots.

How pilots get to 1,500 hours is more important than simply reaching that figure, Sen. Roy Blunt, R-Mo., said.

“Fifteen-hundred hours is not necessarily magic, but however you get whatever training you get is important,” Blunt said.

Sen. Maria Cantwell, D-Wash., said if regional airlines want to weaken safety standards, they shouldn’t be able to fly with names of major airlines, whose more experienced pilots have more training, on the sides of their planes.

“The American public needs to know that these carriers aren’t meeting the same standards,” Cantwell said. “I don’t think anybody wants to get on a plane that says co-pilot not as qualified.”

The Air Line Pilots Association, a union representing 57,000 pilots, said regional airlines would have more pilot recruits if they paid more. The co-pilot of the Colgan flight earned $16,200 per year.

“We will fight any attempt to weaken these air-safety measures,” said Capt. Tim Canoll, the union president.